Retrocyclins: circular defensins active against HIV-1

描述（由申请人提供）：世界上HIV-1最常见的传播途径涉及粘膜表面的性接触。尽管对艾滋病毒-1疫苗的开发给予了很大的关注，但进展缓慢，迫切需要找到针对艾滋病毒-1传播的替代方法。在我们寻找抗HIV-1的新型化合物的过程中，我们发现某些抗菌肽，即来自灵长类动物的阳离子β -防御素，可以有效地在体外抑制HIV-1感染。虽然人类不再产生-防御素肽，但人类骨髓以表达的假基因的形式提供了证据，证明这些肽曾经是我们基因组遗产的一部分。利用其表达的假基因中仍然编码的序列信息，我们重建了这种丢失的人类肽，我们将其命名为反转录细胞周期蛋白。我们确定逆转录细胞周期素和几个类似物抑制病毒进入几乎所有的X4和R5初级分离株和实验室适应的HIV-1毒株迄今为止测试。病毒抑制的性质是特异性的，因为对逆转录细胞周期蛋白结构的轻微修改可以导致抗hiv -1活性的显著变化。许多反转录细胞周期蛋白本质上是非细胞毒性和非溶血性的，因此我们设计了具有高治疗指数的肽类似物。基于我们的初步研究，我们假设a)逆转录细胞周期蛋白类似物将在人体液中保持活性，诱导最小的病毒耐药性，表现出较低的细胞和组织毒性，并且当局部应用于人宫颈阴道器官培养时，是HIV-1传播的有效抑制剂；b)病毒诱导的ifn - β是增强逆转录细胞周期蛋白mRNA表达的必要因素；c)氨基糖苷类药物。抑制逆转录细胞周期蛋白mRNA的过早终止密码子，使人类细胞能够表达功能性的逆转录细胞周期蛋白肽。在一个多学科团队的帮助下，我们将通过以下方法来验证这些假设：1)开发在阴道粘膜中表现出抗HIV-1效力的逆转录细胞周期蛋白类似物，同时最低限度地诱导病毒耐药性；2)表征逆转录细胞周期蛋白表达的调控，并检查人类细胞产生抗HIV-1感染的功能性逆转录细胞周期蛋白的能力。总的来说，这些研究是我们正在进行的努力的自然延伸，以表征和开发逆转录细胞周期蛋白作为局部药物，防止HIV-1的粘膜传播。与公共卫生的相关性（lay statement）： HIV-1最常通过粘膜（如阴道）表面的性接触传播。我们已经发现了一种名为“逆转录细胞周期素”的新分子，它对HIV-1具有活性，并且正在努力开发基于逆转录细胞周期素的药物，以防止HIV-1的性传播。这种以乳霜或凝胶形式出现的药剂，将为脆弱的性伴侣提供一种无形的、有效的保护手段，从而增强他们的能力。

DESCRIPTION (provided by applicant): The most common route of HIV-1 transmission throughout the world involves sexual contact at mucosal surfaces. Although much attention has been focused on vaccine development for HIV-1, progress has been slow and there is an urgent need to find alternative approaches to target the spread of HIV-1. In our search for novel compounds active against HIV-1 we discovered that certain antimicrobial peptides, the cationic theta-defensins from primates, could effectively inhibit HIV-1 infection in vitro. Although humans no longer produce theta-defensin peptides, human bone marrow provided the evidence - in the form of an expressed pseudogene - that these peptides were once part of our genomic heritage. Using the sequence information still encoded within its expressed pseudogene, we recreated this lost human peptide which we named retrocyclin. We determined that retrocyclin and several analogs inhibited viral entry of nearly all X4 and R5 primary isolates and lab-adapted strains of HIV-1 tested so far. The nature of the viral inhibition was specific, in that slight modifications to retrocyclin structure could impart significant variation in anti-HIV-1 activity. Many retrocyclins were essentially non-cytotoxic and non-hemolytic, and thus we have designed peptide analogs with high therapeutic indices. Based on our preliminary studies, we hypothesize that a) retrocyclin analogs will retain activity in human fluids, induce minimal viral resistance, exhibit low cyto- and histotoxicity, and be effective inhibitors of HIV-1 transmission when applied topically to human cervicovaginal organ culture, b) virally-induced IFN-beta is an essential factor that enhances the expression of retrocyclin mRNA, and c) agents such as aminoglycosides, which can suppress the premature termination codon in retrocyclin mRNA, will enable human cells to express functional retrocyclin peptides. With assistance from a multidisciplinary team, we will test these hypotheses by 1) developing retrocyclin analogs that exhibit anti- HIV-1 potency in the vaginal mucosa while minimally inducing viral resistance, and 2) characterizing the regulation of retrocyclin expression and examining the ability to human cells to produce functional retrocyclins that protect against HIV-1 infection. In the aggregate, these studies are natural extensions of our ongoing efforts to characterize and develop retrocyclins as topical agents that prevent mucosal transmission of HIV-1. RELEVANCE TO PUBLIC HEALTH (lay statement): HIV-1 is most commonly spread through sexual contact at mucosal (e.g. vaginal) surfaces. We have discovered a novel molecule called "retrocyclin" that is active against HIV-1, and are working to develop retrocyclin-based agents that can prevent sexual transmission of HIV-1. Availability of such agents, in the form of a cream or gel, would empower vulnerable sexual partners by providing them with an invisible, effective means of protection.